There is known a hybrid vehicle including a differential mechanism which splits a torque of an internal combustion engine into a first motor generator and a drive wheel, and a second motor generator capable of driving the drive wheel. In a power output apparatus which is incorporated in such hybrid vehicle, there is known a control apparatus which calculates a power to be output from an internal combustion engine based on a driving force required to the vehicle, and controls the internal combustion engine, the first motor generator, and the second motor generator so that the calculated power is output and the internal combustion engine is operated at an operational point having high efficiency (see Patent Literature 1).